Should I create a combined list or use a simple parent child relationship?


[Context: Demand forecasting for school books]

I have 5 lists:
- Book (SKU) - e.g. 56084746
- Subject - e.g. "Maths"
- School year - e.g. "5º Grade"
- Type of subject ( e.g. "Mandatory"/ "Not Mandatory") - if a subject is mandatory to every student of that school year

Theoretically, each subject has two parents: the type of subject and the school year.
The solutions I thought were:

1) Simple Parent Child Relationship:

SKU> Subject > Year (e.g: 56084746 > Maths - 5º Grade > 5º Grade)
In this case I had to name the subject according to the school year e.g " Math's - 5º Grade"

The problem is that when using the filter "Type of subject" and the filter "Subject" there will be nonsense combinations (e.g. select Math's -that is mandatory- when the filter "Type of subject" selected is non mandatory)

2) I also thought of using a combined list (combining school year and subject):
SKU > Combined list > Type of subject

What would be the best way of managing the situation considering that:

  • I would like to filter sales according to Subject, School year and type (separately) -
  • When filtering a year, the only subjects I could choose from would be the ones in that school year (e.g. if I select the 5th grade Biology would not be a option)

Thank you so much for your time!